boat "plug" help

[georgiahemi]

Hello all! I have a 55 inch deep vee RC boat plug, that I am going to build a mold of. I have filled in all the imperfections and sanded it. What would be the best kind of paint to put on it for the final coat? I have heard using two part polyurethane gives a great finish. But I can't seem to figure out which one to use, since there are a million different kinds. Is there some kind of paint that I can find at a home depot or ace hardware that will work as the final coat? If so, can it be wet sanded if need be?

Thanks in advance!